Acid treatment is one of the treatments that causes the most problems we see in the office. Many people try to treat their calluses and their warts with acid and they either get too strong of an acid, or they put it on too long and this can cause a sore on the bottom of the foot. This sore is typically called an ulcer and it is caused by having too much acid for a prolonged period of time. Some of the more common ones that you may find over the counter are Compound W or Salinocaine. These can be both purchased and tried over the counter. There are also some over-the-counter remedies for both ingrown toenails and calluses that if you look at the components, they have a component of something called salicylic acid. All of these are acids and they can injure the skin. The problem is they do not know when to stop and so if you keep putting it on, it can break down the top of the skin, which is called the epidermis, and go down into the dermis, which is the area that is the beefy, red area of the skin. I had one patient, he was a man and he thought he had a wart on his heel and he used an acid for many weeks and he came in with a very large wound on his heel and he could not even walk. He was on crutches. We did not need to do much treatment to heal it, all we had to do was have him stop using the acid and it healed up on its own. You can imagine for a healthy young man, that is easy, but if someone, for example, has poor blood flow or poor feeling in their feet, it can create a big problem for them.